With the popularization of smart phones, the smart phones can support more and more applications and have increasingly powerful functions. The smart phones are developing towards diversification and personalization, and become a necessary product in people's life.
At present, with higher and higher demand to security of the smart phones, a plurality of unlocking mechanisms using biological information, for example fingerprint recognition, face recognition and iris recognition, are proposed. The face recognition has a faster unlocking speed and a higher recognition success rate, and thus has become the first choice of most smart phones.